The answer to the problem of non paying rake back affiliates is already solved. From what i know apart from us(RoyalCardClub) there are very few more rooms to pay the players.
Each affiliate that want to advertise rake back we set it for that and automatically retain the player comission that is available for withdraw anytime in the player account. Thus the affiliate have access only to his money and players can see the % and the amount they are paid directly from us, exclduding with this the affiliate fraud.